Among the air conditioning systems used in office buildings and residential buildings, split-type systems having an indoor unit and an outdoor unit connected by communication pipes are widely used. For example, in the multi-split type air conditioning system (multiple-indoor-unit split-type air conditioning system) used in office buildings, the outdoor unit is installed on the roof or other location and the indoor units are installed in the ceiling or other location of each floor, the outdoor unit and indoor units being connected together by a gaseous refrigerant pipe and a liquid refrigerant pipe to form a refrigerant circuit.
The outdoor unit of such an air conditioning system has a gas-side shut-off valve and a liquid-side shut-off valve at the terminal ends of the refrigerant circuit there-within. These shut-off valves are switched from the closed state to the open state after the outdoor unit and the indoor units have been installed onsite and the gaseous refrigerant pipe and liquid refrigerant pipe from the indoor units are connected. As a result, refrigerant can flow between the outdoor unit and the indoor units.
In a conventional air conditioning system, the gas-side shut-off valve 118 and the liquid-side shut-off valve 119 of the outdoor unit 102 are arranged side by side along the front panel 121 of the casing as shown in FIG. 7 or in front of and in rear of each other along the side panel 122 of the casing (not shown). Since the two shut-off valves 118, 119 are closely adjacent to each other, it is easier to complete the work of applying thermally insulating tape to the gaseous refrigerant pipe and liquid refrigerant pipe, which are connected to the pipe connecting ports 118a, 119a of the shut-off valves 118, 119 and drawn out of the outdoor unit, and the work of covering the valve area with a decorative metal plate.
When the pipe connecting ports of the gas-side shut-off valve and liquid-side shut-off valve are aligned along one panel of the casing as shown in FIG. 7, there is not a problem if the refrigerant pipes are drawn out of the outdoor unit in a direction perpendicular to said panel. However, if the pipes are drawn in a direction generally parallel to said panel, the pipes will interfere with each other unless they are drawn out at different heights. While the problem of interference is resolved by installing the gaseous refrigerant pipe and liquid refrigerant pipe at different heights, there are cases in which the two pipes cannot be installed at different heights due to space restrictions or other conditions related to the installation work. The surrounding conditions differ at each installation site and there is no guarantee that the conditions of a particular site will allow the pipes to be drawn out in a convenient direction.
In such situations, the gaseous refrigerant pipe and the liquid refrigerant pipe end up following a path that is bent more than would otherwise be necessary as a result of avoiding interference between the pipes. Consequently, the cost of installing the air conditioning system and the time required for installation both increase.